Construction set

ABSTRACT

A structural element of a construction set has an elongated web having two transversely spaced longitudinally extending margins, a first flange extending along one of the margins, a second flange extending along the other of the margins and a plurality of cutouts spaced along the element.

[ 1 June 24, 1975 10/1972 Ward et 7/1973 Wall FOREIGN PATENTS OR APPLICATIONS CONSTRUCTION SET [75] Inventor: Dieter Specht, Dhunn, Germany 186,862 12/1963 631,559 11/1961 Canada.................................

[73] Assignee: Masyc AG, Laufen, Switzerland [22] Filed: May 23, 1973 [21] Appl. No.: 363,045

Primary ExaminerErnest R. Purser Assistant Examiner-Car1 D. Friedman U-S. Cl-

Attor'ney Agenl 0r Firm Michael Striker 52/574; 52/585; 52/588; 52/732; 52/758 A;

[57] ABSTRACT A structural element of a construction set has an elon- [51] Int. C1.F04c 3/08 52/645, 721, 729, 720,

gated web having two transversely spaced longitudinally extending margins, a first flange extending along one of the margins, a second flange extending along the other of the margins and a plurality of cutouts spaced along the element.

[58] Field of Search [56] References Cited UNITED STATES PATENTS 52/729 X 52/732 X 6 Claims, 12 Drawing Figures 3,284,971 11/1966 Attwood... 3,332,197 7/1967 Hinkle PATENTEDJUN 24 I975 SHEET FIGA FIGS

CONSTRUCTION SET BACKGROUND OF THE INVENTION The invention relates to a construction set, and more particularly to a set of structural elements to be used for construction of frames for conveyors, shelves or the like.

There is a need in various industrial establishments for a simple and inexpensive construction set using interchangeable structural elements, which can be easily assembled and disassembled and which is not limited to only one use but which is rather versatile permitting its use for a variety of purposes, such as support frames, particularly for belt or roller conveyors or gravity conveyors, regular or continuous shelving or similar constructions.

In the following disclosure, the construction set will be described in connection with its use for conveyors, but is not limited thereto since the versatility of the structural elements will become apparent and their use in other embodiments is within the ordinary skill of the user.

The support frames of the known conveyors generally comprise two beams arranged on both sides of the conveyor and having profiled cross-sections. Such beams are rigidly interconnected either by screw coupling or welding together either directly or utilizing transverse beams or lugs, and they are usually supported on associated support beams or undestructures. These two beams support the shafts of the rollers, and corresponding bores are provided in the two beams for accommodation and attachment of the roller shafts. Since these constructions are usually made in order so as to suit a particular purpose, any modification of such constructions or diversion of the structural elements thereof to a different use are extremely difficult, if not impossible to achieve.

SUMMARY OF THE INVENTION It is an object of the present invention to avoid the drawbacks of the prior art.

It is a particular object of the present invention to provide a construction set whose structural elements are interchangeable, inexpensive to produce and simple to assemble.

A concomitant object of the invention is to provide a construction set having a wide field of application and simple adaptability to various space conditions and diversified utilizations.

A still more particular object of the invention is to provide a construction set for conveyors r shelvings which consists of a limited number of types of structural and interconnecting elements and which permits easy assembly and disassembly of a construction suited to a particular purpose and/or conversion from one such construction to a different one.

In pursuance of the above objects and others which will become apparent hereinafter, one feature of the invention resides in provision of a substantially sigmashaped universal structural element comprising a web and two flanges which are similar in appearance but different in size. According to the invention, one of the flanges is larger than the other one and defines a channel whose inner dimensions correspond to the outer dimensions of the smaller flange. By this expedient,- it is possible to telescopically insert the above-rnentioned structural element into another one having the same configuration but rotated about its longitudinal axis by an angle of in relation to the first structural element, in such a manner that the smaller flanges of the respective structural elements are accommodated in the channels of the associated structural elements and the webs of these structural elements adjoin each other. The structural element according to the invention is further provided with a plurality of cutouts for accommodation of screws, pins, shafts or similar connecting or supporting elements.

In a currently preferred embodiment of the invention, the structural elements are provided with two rows of cutouts, each row being arranged parallel to one of the flanges in an immediate vicinity thereof. For easy assemblage of such structural elements and for their interchangeability, as well as for increasing the amount of various uses for these elements, the individual cutouts are not only arranged in rows with constant spacing between the centers of such cutouts, but are also aligned in the transverse direction of the web of such structural element so as to form a rectangular array of cutouts. This results in a perfect alignment of all of the cutouts of one row in one structural element with the other row of cutouts in the other element when these elements are telescopically inserted into each other as described above, and also in other advantages which will become apparent later. The main purpose of such regular arrangement of the cutouts is, however, to facilitate alignment, assemblage and joining of such structural elements so as to suit a particular purpose, and to assure interchangeability of such elements.

While it would be quite sufficient if all the cutouts had the same, for instance circular shape, it is another feature of the invention that at least every other of the cutouts of one row is provided with an enlarged portion, thus resembling the letter T. To advantage, this enlarged portion is provided in an inclined portion of the web where the web merges into the flange, so that it serves for facilitation of insertion of elements to be supported in said cutouts into the same. This arrangement is particularly suitable for insertion of such elements as shafts or crossties provided with grooves to be embedded in such cutouts, since the insertion is then very simple and these elements are secured in such cutouts without being free to move in their longitudinal directions. Furthermore, it is advantageous if at least a part of the cutouts has a multilateral, such as rectangular or hexagonal, shape so that shafts, crossties or the like may be inserted thereinto by their correspondingly shaped ends and thus be supported therein without being free to rotate.

In addition to the above-described structural elements, the construction set also comprises a base member which is insertable into the structural element or the assembly of two such elements as discussed earlier, and a head member similar to the base member but additionally comprising lugs between which a flange of an additional structural element may be inserted so as to be surrounded by the lugs and the head member and firmly held by the same. Both the base member and the head members comprise connecting portions adapted for insertion into the structural elements and provided with elongated cutoutswhose distance corresponds to the distance between the two rows of cutouts in the structural elements. When such a member is introduced into such structural element, at least one of the cutouts of the structural element will be in alignment with each of the two elongated cutouts of such a member, so that a connecting means, such as a screw or the like, can be inserted therein and the structural element and the member can be firmly attached to one another.

A construction set according to the invention further comprises a connector having a plate which is preferably disc-shaped and is provided with two arcuate elongated holes extending along a circular section whose center coincides with the axis of rotational symmetry of the disc-shaped plate and whose diameter corresponds to the distance between the two rows of cutouts of the structural element. The connector is further provided with means for attaching the disc-shaped plate to another structural element. When using such a connector, it is possible to attach the two structural elements to each other so that their longitudinal axes enclose an angle with each other, thus contributing to the versatility of applications of such structural elements.

In a currently preferred embodiment of the invention, the means for attaching the plate to the other structural element comprise two pins insertable into the cutouts of one row of cutouts of the other structural element, and a bore which becomes aligned with a cutout belonging to the other row of cutouts when the aforementioned pins are inserted into the cutouts of the one row, so that the connector can be secured to the other structural element by only one screw. Two other screws are accommodated in the elongated arcuate cutouts of the disc-shaped plate and extend through two cutouts of the one structural element aligned in the transverse direction of the web, so that the one structural element can be attached to the connector and thus to the other structural element at an angle in relation thereto.

According to a further embodiment of the invention, the connector is provided with a cylindrical bore whose axis coincides with the axis of rotation of said discshaped plate and which serves for accommodation of either a shaft or a bearing, such as a roller bearing or the like, supporting such shaft.

A further feature of the present invention is the provision of a support assembly which is adapted for attachment to the aforementioned structural element and which serves for support of shafts of rollers or cylinders which rotate about the same, and wherein the axes of the shafts enclose an angle with one another in a plane defined by the longitudinal direction of the structural element and a line perpendicular to the surface of the web. In this manner, it is possible to provide a trough-- shaped conveyor or roller support for a belt of a belt conveyor.

A very important feature of the construction set according to the invention is the cross-sectional shape of the structural members, which is such that one such structural member can be telescopically inserted into another one after being rotated by an angle of 180 about its longitudinal axis in relation to the other structural element. This is a consequence of the particular configuration of the flanges, where one of the flanges of each structural element is larger than the other one and defines a channel whose inner dimensions correspond to the outer dimensions of the smaller flange of the other structural element. So, after one of the structural elements has been rotated by an angle of 180 about its longitudinal axis, it can be telescopically inserted into the other structural element so that the smaller flange of the one structural element is accommodated in the channel defined by the larger flange of the other structural element whose smaller flange is, in turn, accommodated in the channel defined by the larger flange of the one structural element. The currently preferred sigma-shaped configuration of the structural elements has a two-fold advantage. First of all, when the structural elements are telescopically inserted into one another, the webs of these structural elements extend parallel to each other leaving virtually no gap between each other, so that they can be easily joined by simple joining means such as screws without deformation which might result if the webs were spaced apart. On the other hand, since the flanges project beyond the plane of the web outwardly ofthe conveyor rollers, the shafts of such rollers passing through the cutouts in the web and secured to the webs by nuts or other suitable fastening means do not project beyond the plane defined by the flanges, so that the danger of a passer-by catching his cloth thereon or suffering an injury is substantially reduced if not eliminated.

Even though the sigma-shaped configuration of the structural elements is currently preferred, the invention is by no means limited thereto. However, this advantageous configuration may easily be modified within the skill of an artisan without departing in any way from the basic idea of the invention and sacrificing its advantages. So, for instance, it is quite conceivable that the structural elements may have a substantially C-shaped configuration with flanges having such shapes that one of the flanges of one element may be telescopically inserted into an associated flange of another element after one of the structural elements has been rotated by an angle of Such a combination of two structural elements already satisfies some, even though not all, of the requirements set for such combinations in accordance with the invention. Therefore, such mofidication of the structural elements is intended to be understood as falling into the scope of the present invention.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, such as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view ofa structural element according to the invention; I

FIG. 2 is a cross-sectional view of the structural element along the line II-II of FIG. 1;

FIG. 3 is a perspective and partially exploded view of a conveyor utilizing structural elements of the construction set according to the invention;

FIG. 3a is a side view of a different embodiment of a broken-away end portion of the shaft to be used in a conveyor according to FIG. 3;

FIG. 4 is a perspective view of a trough-shaped conveyor utilizing structural elements of the construction.

set according to the invention;

FIG. 5 is a cross-sectional view along the line VV of FIG. 4;

FIG. 6 is a rear view of a connector of the construction set according to the invention;

FIG. 7 is a front view of the connector shown in FIG. 5;

FIG. 8 is a cross-sectional view along the line VIII- VIII of FIG. 7;

FIG. 9 is a cross-sectional view along the line IXIX of FIG. 7;

FIG. 10 is a perspective view of the combination of two structural elements according to the invention utilizing the connector as shown in FIG. 7 for joining such structural elements so as to enclose an arbitrary angle to each other; and

FIG. 11 shows another embodiment of the structural element according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be first explained with reference to FIGS. 1 and 2 of the drawing showing one structural element 15 of the construction set. FIG. 2 shows in detail the advantageous configuration of such structural element having a shape resembling the Greek letter sigma and having an elongated web 16 and two flanges 17 and 18 extending along the entire length of the web 16.

The structural element of girder 15 may be made of metallic, but also synthetic plastic, material. The flanges l7 and 18 have similar configurations but different dimensions for reasons which will be explained later. The flange 17 comprises an inclined portion 20 which is integral with the web 16 and which merges into a portion 21 which is parallel with the web 16. This portion 21 in turn merges into a portion 22 which is perpendicular to the web 16 and which has a lip 23 extending parallel to the web 16. Since the flanges 17 and 18 are similar to each other, the same numerals have been applied to the flange 18 with primes added.

The portions 20, 21, 22 and 23 of the flange 17 define among themselves a channel whose inner dmensions substantially correspond to the outer dimensions of the portions 20, 21', 22', and 23 of the flange 18. FIG. 2 further shows an additional structural element or girder 15 having the same configuration as the girder 15; for the sake of clarity, this girder 15' is shown in broken line. It can be seen that the position of this girder 15 is reversed in respect to the girder 15, i.e. the girder 15' has been rotated by an angle of 180 about its longitudinal axis in respect to the girder 15. In such a position, the girder 15' can be easily telescopically inserted into the girder 15 so that the flange 17' of the additional girder 15' surrounds the flange 18 of the girder 15 and the flange 18' of the additional girder 15' is accomodated in the flange 17 of the girder 15. When the girders 15 and 15 are so telescopically inserted into each other, the web 16 of the girder 15 is adjacent, and contacts, the web 16' of the girder 15. Thus the girders 15 and 15' are secured to each other if no forces acting in the longitudinal direction of the girders are present.

FIG. 1 shows that the girder 15 is provided with a row 24 of cutouts 26 and 29 extending along the flange 17, and with a further row 25 of cutouts and 31. In the shown embodiment, the cutouts 26 and 29, as well as cutouts 30 and 31, alternate, the center distance of these cutouts being the same; that is, for instance, that the distance between the center of one cutout 26 and the center of an adjacent cutout 29 is the same as between the center of this cutout 29 and the center of the next successive cutout 26, etc. The cutouts 26 are substantially T-shaped, each having an enlarged portion 27 and a narrow portion 28. While the narrow portion 28 is located in the web 16 of the girder 15, the enlarged portion 27 is situated in the inclined portion 20 of the flange 17. The other cutouts 29 as shown in the preferred embodiment are round holes.

The other row 25 of cutouts comprises two alternating types of cutouts 30 and 31, the cutouts 30 being round, and the cutouts 31 hexagonal holes. The cutouts 26 are aligned with the cutouts 30, and the cutouts 29 are aligned with the cutouts 31, in the transverse direction of the web 16 so as to form a regular orthogonal grid for reasons which will become apparent hereafter.

A number of such girders 15 can be utilized for constructing a framework for a roller conveyor, as will be explained in the following with reference to FIG. 3, showing broken-away portions of two such girders, which are mutually spaced so as to define the conveyor. These girders may be supported on any arbitrary understructure, but preferably on a support 35 as illustrated. It will be understood that the lateral girders 15 of the conveyor can be combined with other such girders 15 (not shown) so as to construct a conveyor of any desired length. The particular method of connection of the successive girders 15 to each other is a matter of obvious choice, but these girders can be preferably interconnected by sections of girders which are not shown but which have the same configuration bar the length as the girders 15 whose longitudinal dimensions are chosen so as to assure interconnection of the girders without interfering with the function of the conveyor.

The support 35 comprises two girders l5 telescopically inserted into each other, a base member 36 comprising a base plate 40 and a connecting portion 38 so configurated as to be insertable into the channels defined by the smaller flanges 18 of the girders 15 and provided with two elongated holes 39, and a head member 37 comprising a head plate 41 having two lugs 42 and 43 and a connecting portion 38' insertable into the above-mentioned channels of the flanges 18 of the girders l5 and provided with two elongated holes 39'. The lug 42 is provided with a hole 44 which is so situated that it can be aligned with one of the cutouts 30 or 31 of the row 25. When such a support is to be erected, the girders are inserted into one another and fastened to each other by conventional fasteners, such as screws, in such a manner that their combined length is somewhat smaller than the intended height of the support 35. Then the head member 37 and the base member 36 are inserted into the channels provided in the girders l5, and the height of the support 35 is adjusted to the desired value by passing screws or similar fasteners through the elongated holes 39 and 39' of the head member 37 and the base member 36 and the associated cutouts 26 and 30 or 29 and 31 of the girders 15 and fastening the head and base members to the girders in any position limited by the length of the elongated holes. Subsequently thereto, the support 35 is erected and a lateral girder 15 is inserted between the lugs 42 and 43 so that the hole 44 in the lug 42 becomes aligned with a cutout of the row 25 and any suitable fastening means, preferably screws, are inserted through these holes and fastened so as to provide for a rigid attachment of the lateral girder 15 to the head member 37 and thus the support 35. It is evident from the above that the spacing of the elongated holes 39 or 39 must substantially correspond to the spacing of the two rows 24 and 25 of cutouts in the girders 15. It goes without saying that, while only one support has been shown, at least one support will be associated with each lateral girder and all of them will have a construction similar to the described embodiment.

FIG. 3 further shows a roller shaft 48 which is accommodated in two cutouts 26, each being associated with one lateral girder 15. It is to be understood that the conveyor comprises a plurality of such shafts 48, but only one has been shown for illustrative purposes In the shown embodiment, the shaft 48 has two tapered ends and is secured to the girders by a nut 50 at each of the ends. The shaft 48 supports rollers 49 for rotation about its axis.

The flanges l7, i.e. the upper flanges in the illustrated embodiment, serve as lateral limitations of the conveyor, and as guide means for the articles to be conveyed. This is valid whether or not the rollers are driven; however, if a chain or belt drive is used for driving the rollers, which in such a case would be shaped as cylinders extending substantially the entire width of the conveyor, a further advantage is achieved, namely that the driving chain of driving belt may be accommodated in the channels defined by the flanges 17 and 18 of the individual girders 15, so that the danger of injury resulting from contact with the moving driving chain or belt is virtually eliminated. The same is of course valid if the chains or the belts served for deceleration of the rollers.

FIG. 3a shows another embodiment of the end portion of the shaft 48' wich permits a particularly simple and fast assembling of a conveyor. Instead of being tapered as the shaft 48, the shaft 48' is provided with a slot 51. The shaft 48' which is provided with such slots 51 at both ends is then inserted into the associated cutouts 26 of the lateral girders 15 so that the shaft 48 is first inserted into the enlarged portion 27 and then pushed into the narrow portion 28 so that the walls of the slot 51 externally surround the web 16 of the girder 15. Thus, the shaft is secured both against rotation about, and displacement in the direction of, its longitudinal axis.

A further embodiment of the invention is shown in FIGS. 4 and 5. Here, short girder sections 15" are arranged between two of the girders 15 and connected to the latter via tie-rods 54. The girders 15 have openings 26 through which the tie-rods 54 extend; nuts 55 are threaded onto the outer ends of the tie-rods to hold the same in place. The webs 16 of the girder sections 15" serve as a mount for a support assembly 58 which, although being shown as of three-part construction, could also be of onepart construction.

FIG. 4 shows that the assembly 58 has two outer parts or arms 60 which are mounted via respective mounting plates 59 on the web 16 of the associated girder section 15"; the upper end-of each arm 60 is formed with a slot 61. A further part or center support 63 is mounted on the web 16 intermediate the arms 60; it has the form of an inverted V and is provided with apertures which each accommodate one end of the shaft of a cylindrical roller 62, whereas the other end of the same shaft is accommodated in a respective one of the slots 61. Evidently, with this construction it is possible to either erect a through-shaped roller conveyor, or, if desired, to use the rollers 62 as supports for a conveyor belt.

FIGS. 6-9 show a component, namely the cross-piece 70, which substantially increases the versatility of the construction set according to the present invention. The cross-piece has a disc portion 71 of approximately frustoconical cross-section, the rear side of which is provided with two pegs whose spacing corresponds to that of the cutouts 26. The pegs have undercuts 73 adapted to the configuration of the slots 51 (FIG. 3a), thus permitting the pins to be retained in two adjacent cutouts 26 of a girder 15. A tapped bore 74 of the disc-portion 71 registers with the cutout 31 when a connection is established in this manner, so that a screw may be threaded through the cutout 31 into the tapped bore, thereby permitting reliable securing of the cross-piece 70 to the web 16 of a girder 15.

The cross-piece is further provided with two arcuate openings 75 located on an imaginary circle and bounded at the rear side of the disc portion 71 by an annular projection 76, as shown in FIG. 9. A recess 77 is formed centrally intermediate the openings 75 and adapted to accommodate as shown in broken lines in FIG. 8 the bearing 78 of a shaft, or any other appropriate component. This makes it possible to mount shafts, axles or the like between two girders 15 each of which is provided with one of the cross-pieces 70.

FIG. 10 illustrates a further, and particularly advantageous, use of the cross-piece 70. It will be seen that the cross-piece can be employed to mount two girders 15, 15" at desired angles relative to one another. To do so, the cross-piece is secured to one of the girders, here the girder 15, in the manner described above. The other girder, here the girder 15", is connected to the cross-piece by passing screws or bolts through it and through the openings 75. The girders can evidently be placed at any desired angle relative to one another, within the limits imposed by the circumferential length of the openings 75.

It is clear that modifications of the examples provided herein are possible and will readily suggest themselves to those skilled in the art. However, even the limited examples which have been described will already indicate the great versatility of the novel construction set. In particular, it is possible with this set to erect any kind of supporting framework, especially for conveyors, shelving, racks or the like. Moreover, once erected, such a construction can be readily modified.

It is to be noted that the ends of the shafts 44 and the nuts threaded onto them (see FIG. 3), the ends of the shafts 48' (see FIG. 3A), the ends of the rods 54 with the nuts 55 (see FIG. 4) and the bolts or screws 79 (see FIG. 10) are all recessed within the width of the flanges 17,18. This is an important safety factor, because it prevents clothing or body portions of personnel from becoming snagged on these components. The wider portions 27 of the cutouts 26 are located in the inclined portions 20 of the girders 15; this facilitates the insertion of an axle 48, rod 54 or the like into the narrower portion 28 via the wider portion 27. Yet, the provision of these wider portions does not result in any significant weakening of the strength of the girders 15 which is, of course, also an important consideration.

The embodiment of FIG. 11, finally, differs from the preceding embodiments in that the girder illustrated in that Figure has portions 21" and 23" which are wider than in the other embodimentsv Cutouts, such as the ones designated with reference numeral 29 in the preceding embodiments, are in this instance provided only in the web 16" and in the portions 23". The purpose of this construction is to provide a girder of improved appearance while, nevertheless, retaining substantially all of the advantages inherent in the girders according to the preceding embodiments.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a construction set, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and, threfore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a construction set, a structural element comprising an elongated web having a first and a second transversely spaced longitudinally extending margins, 21 first flange extending along said first margin, a second flange extending along said second margin, and a plurality of cutouts spaced along said elements and including a first row of equidistant cutouts arranged parallel to said first margin adjacent said first flange, and a second row of equidistant cutouts arranged parallel to said second margin adjacent saidsecond flange, the cutouts of said first row being aligned in the transverse direction of said web with the corresponding cutouts of said second row; and a disc-shaped connector having an axis of rotational symmetry and provided with two elongated arcuate holes extending along a circular are having a center located within said axis of rotational symmetry and a diameter corresponding to the distance between said first and second rows of cutouts, said connector further including means for accommodation in said cutouts of said structural element.

2. A construction set according to claim 1, wherein said second flange has a configuration similar to said first flange and smaller dimensions than the corresponding dimensions of said first flange.

3. A construction set according to claim 1, wherein said structural element has a substantially sigmashaped configuration.

4. A construction set according to claim 1, wherein said means for accommodation of said connector in said cutouts comprises two pins and a bore which are arranged with mutual spacing corresponding to the spacing of associated cutouts of said structural element.

5. A construction set according to claim 1, further comprising a cylindrical bore having an axis of rotational symmetry coinciding with said axis of rotational symmetry of said connector.

6. A construction set according to claim 1, comprising a further structural element having the same configuration as said one structural element, wherein said means for accommodation of said connector in said cutouts attach said connector to said one structural element, and wherein attachment means are inserted into said arcuate holes of said connector and in two cutouts belonging to said first and said second rows of cutouts of said further structural element for attachment of said further structural element to said connector at an arbitrary angle in respect to said one structural element within an angular range determined by the shape of said arcuate holes. 

1. In a construction set, a structural element comprising an elongaged web having a first and a second transversely spaced longitudinally extending margins, a first flange extending along said first margin, a second flange extending along said second margin, and a plurality of cutouts spaced along said elements and including a first row of equidistant cutouts arranged parallel to said first margin adjacent said first flange, and a second row of equidistant cutouts arranged parallel to said second margin adjacent said second flange, the cutouts of said first row being aligned in the transverse direction of said web with the corresponding cutouts of said second row; and a disc-shaped connector having an axis of rotational symmetry and provided with two elongated arcuate holes extending along a circular arc having a center located within said axis of rotational symmetry and a diameter corresponding to the distance between said first and second rows of cutouts, said connector further including means for accommodation in said cutouts of said structural element.
 2. A construction set according to claim 1, wherein said second flange has a configuration similar to said first flange and smaller dimensions than the corresponding dimensions of said first flange.
 3. A construction set according to claim 1, wherein said structural element has a substantially sigma-shaped configuration.
 4. A construction set according to claim 1, wherein said means for accommodation of said connector in said cutouts comprises two pins and a bore which are arranged with mutual spacing corresponding to the spacing of associated cutouts of said structural element.
 5. A construction set according to claim 1, further comprising a cylindrical bore having an axis of rotational symmetry coinciding with said axis of rotational symmetry of said connector.
 6. A construction set according to claim 1, comprising a further structural element having the same configuration as said one structural element, wherein said means for accommodation of said connector in said cutouts attach said connector to said one structural element, and wherein attachment means are inserted into said arcuate holes of said connector and in two cutouts belonging to said first and said second rows of cutouts of said further structural element for attachment of said further structural element to said connector at an arbitrary angle in respect to said one structural element within an angular range determined by the shape of said arcuate holes. 